This application is based on patent application Nos. 9-360605, 9-360606, 9-360607, and 9-360608 filed in Japan, the contents of which is hereby incorporated by reference.
This invention relates to an image generating apparatus, particularly to an image generating apparatus which partially senses an image of an object while dividing it into a plurality of blocks, combining the respective partial images by applying an image processing to generate a photographed image of an whole object.
Conventionally, methods for improving a resolution have been proposed in connection with electronic cameras using CCDs or like solid-state image sensing elements, according to which methods an object is partially sensed while being divided into a plurality of blocks and a sensed image of the entire object is generated by combining the respective partial images in such a manner as to paste them together.
Japanese Unexamined Patent Publication No. 6-141246 discloses an image generating apparatus as follows. An object light image is divided into a plurality of parts in such a manner that boundary portions thereof overlap with each other, and the respective partial light images are sensed by a plurality of sensing elements. The partially sensed images are combined in such a manner as to be pasted together at their overlapping boundary portions, thereby obtaining an image of the whole object. In this apparatus, if there is an image displacement in the boundary portions, the image displacement is corrected before the combination of partial images. The correction of image displacement is performed by defining the displacement in the terms of a parallel movement and a rotational movement, and moving the adjacent partial images in parallel or rotation.
Japanese Unexamined Patent Publication No. 3-210873 discloses an image generating apparatus as follows. An image of an original larger than an image reading area is read part by part in such a manner that boundary portions of partial images overlap with each other. These partial images are recorded on a recording sheet while being connected at the overlapping portions, thereby forming an image of the whole original.
Japanese Unexamined Patent Publication No. 9-23330 discloses an image processing apparatus in which an image combination is performed by extracting particular areas having less brightness change in boundary portions of adjacent partial images, and combining the partial images on the reference of the particular areas.
As smoothing of image data at combining portions, there has been the linearly weighted-averaging as shown in xe2x80x9cImage Analysis Handbookxe2x80x9d published by Tokyo University Publishing. Such smoothing is performed to smoothen density variations between adjacent partial images by mixing image data in specified portions of the adjacent partial images in a predetermined proportion.
In the case that an object is sensed while being divided into a plurality of parts and an image of the entire object is obtained by combining the partial images in such a manner as to paste them together, it is convenient if a photographer can immediately monitor an obtained photographed image (i.e., combined image). However, in the conventional image generating apparatus, the image of the whole object is obtained by, after sensing the object part by part, combining a plurality of partially sensed images in such a manner as to paste them together. Accordingly, the photographed image (image of the whole object) the photographer wants to monitor can be obtained only after the image combination, and he/she cannot monitor the photographed image immediately after a shutter release operation. Therefore, in high resolution photographing, there is a blank period between the shutter release operation and a point of time when the photographed image can be monitored in a monitor-display operation of the photographed image. This results in a reduced operability.
In the divisional sensing, a distortion is likely to occur in the boundary portion of each partial image due to a camera shake or a characteristic performance of a camera. In particular, in the case of generating a plurality of partial images by changing the sensing direction or the optical axis with a single image sensor, a distortion is likely to occur in the boundary portion of each partial image due to an oblique sensing caused by the change in the optical axis.
In the apparatus of Japanese Unexamined Patent Publication No. 6-141246, the combination of partial images is performed based on information on displacements in a limited area of the overlapping boundary portion. Accordingly, there is a likelihood that a difference in the image distortion correction for the combination becomes noticeable in the respect of areas other than the boundary portions, e.g., a likelihood that a line image extending over the adjacent two partial images has a distortion or a bent in the boundary portions. If there is not a peculiar image for image combination in the boundary portions, it will become difficult to attain accurate image combination.
The parallel or rotational movement is performed based on information on an image displacement in such limited areas as the boundary portions. Accordingly, a disagreement caused by the parallel or rotational movements makes the accurate image combination very difficult.
In the image processing apparatus of Japanese Unexamined Patent Publication No. 9-23330, a delicate operation is required to extract particular areas having less brightness change in the boundary portions. Accordingly, there has been hoped a further improvement to generate a combined image with a reduced displacement.
In the image processing using the linearly weighted-averaging, a line image having a displacement between adjacent partial images can be corrected into a line image having no displacement. However, the edge of the corrected line image becomes dull or cannot have a sharp contrast as the brightness level is lowered in the corrected image.
It is an object of the present invention to provide an image generating apparatus which has overcome the problems residing in the prior art.
According to an aspect of the invention, an image generating apparatus comprises: an image sensing device which senses an image of an object; an image processor which processes a sensed image; a display device which displays a processed image; and a controller which controls the image sensing device, the image processor, and the display device so that: the image sensing device executes a first sensing of sensing a whole image in a specified region of the object, and a second sensing of sensing partial images in a plurality of divided parts of the specified region; the image processor combines the plurality of sensed partial images into a single image corresponding to the whole image in the specified region; and the display device displays the sensed whole image before the combination of sensed partial images.
According to another aspect of the invention, an image generating apparatus comprises: an image sensing device which senses an image of an object; an image processor which processes a sensed image; and a controller which controls the image sensing device and the image processor so that: the image sensing device executes a first sensing of sensing a whole image in a specified region of the object, and a second sensing of sensing partial images in a plurality of divided parts of the specified region; and the image processor combines the plurality of sensed partial images into a single image corresponding to the whole image in the specified region, each sensed partial image being transformed with reference to the sensed whole image.
According to still another aspect of the invention, an image generating apparatus comprises: an image sensing device which senses an image of an object; an image processor which processes a sensed image; and a controller which controls the image sensing device and the image processor so that: the image sensing device executes a first sensing of sensing a whole image in a specified region of the object, and a second sensing of sensing partial images in a plurality of divided parts of the specified region; and the image processor combines the plurality of sensed partial images into a single image corresponding to the whole image in the specified region by determining respective positions of the sensed partial images with reference to the sensed whole image, and combining the sensed partial images with one another based on the determined positions.
According to yet still another aspect of the invention, an image generating apparatus comprises: an image sensing device which senses an image of an object; an image processor which processes a sensed image; and a controller which controls the image sensing device and the image processor so that: the image sensing device senses partial images in a plurality of divided parts of a specified region of the object, a boundary portion of each partial image overlapping a boundary portion of an adjacent divided part; and the image processor combines the plurality of sensed partial images into a single image corresponding to the whole image in the specified region by correcting the level of respective sensed partial images based on image data in the boundary portion thereof, averaging the image data with a predetermined weight to generate boundary images, applying an edge enhancement to the boundary images, and combining the edge enhanced boundary images with the other portions of the corrected partial images than the boundary portions.